DNA structure

What are the three key properties of genetic material?

Contains information, replicates accurately, capable of change (mutation).

What significant discovery did Flemming make in the mid 1800s regarding chromosomes?

Flemming discovered chromatin in the nucleus using microscopes.

What did Friedrich Miescher isolate in 1868?

He isolated 'nuclein', which is nucleic acid, from pus.

According to Boveri's chromosomal theory of inheritance, what role do chromosomes play?

Chromosomes are responsible for inheritance, with eggs containing half the number of chromosomes.

What was Griffith's experiment with Streptococcus pneumoniae about?

He discovered that non-virulent IIR bacteria could be transformed into virulent IIIS by something in dead IIIS bacteria.

What was the significance of the work by Avery, MacLeod, and McCarty in 1944?

They demonstrated that DNA is necessary for transformation in bacteria.

What did Hershey and Chase demonstrate in their 1953 experiment?

They demonstrated that DNA, not protein, is the genetic material in bacteriophages.

What findings did Wilkins, Watson, and Crick present about the structure of DNA?

They revealed that DNA is a double-stranded helix composed of a sugar-phosphate backbone and base pairs.

What are the differences between DNA and RNA?

DNA is a stable double-stranded polymer with deoxyribose sugar, while RNA is typically single-stranded with ribose sugar.

What is complementary base pairing in DNA?

Adenine pairs with thymine (2 hydrogen bonds) and guanine pairs with cytosine (3 hydrogen bonds).

What do the terms euchromatin and heterochromatin refer to?

Euchromatin is less compact and contains actively expressed genes, whereas heterochromatin is more compact and consists of DNA that is not transcribed.

What is a karyotype?

A karyotype is the complete set of chromosomes in an organism.

How is DNA packaged into chromosomes?

DNA is wrapped around histones to form nucleosomes, which are further compacted by scaffold proteins.

What type of DNA do plants have in their chloroplasts and mitochondria?

Plants have circular DNA in their chloroplasts and mitochondria.

What structures are formed at the ends of chromosomes and why are they important?

Telomeres are found at the ends of chromosomes and are important for maintaining chromosome stability.

What is the composition and condition of eukaryotic genomes compared to prokaryotic genomes?

Eukaryotic genomes contain linear chromosomes housed within a nucleus, while prokaryotic genomes consist of a single circular DNA molecule without a nucleus.